Unable to add MCP servers

[tensor5]

Adding an MCP server, both http or stdio, fails with this error:

I tried the master branch, built using nix build, this is the error in console:

Traceback (most recent call last):
  File "/nix/store/wfqg2k1zrsf7qkmaj5pblfkqcsiqz0w0-newelle-0.9.6/share/newelle/newelle/ui/settings.py", line 1671, in add_thread
    added = mcp_handler.add_mcp_server(
            ^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/nix/store/wfqg2k1zrsf7qkmaj5pblfkqcsiqz0w0-newelle-0.9.6/share/newelle/newelle/integrations/mcp.py", line 176, in add_mcp_server
    tools = self.sync_get_tools_stdio(command, args or [], env)
            ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/nix/store/wfqg2k1zrsf7qkmaj5pblfkqcsiqz0w0-newelle-0.9.6/share/newelle/newelle/integrations/mcp.py", line 436, in sync_get_tools_stdio
    from mcp.client.stdio import stdio_client
ModuleNotFoundError: No module named 'mcp'

[FrancescoCaracciolo]

Nix flake is outdated, use flatpak